Research on Speeds at Roundabouts for the Needs of Sustainable Traffic Management

Abstract

Knowledge of the characteristics of speed at roundabouts is very important in design procedures, simulation models, and determining the influence of these roundabouts on traffic conditions in a street network. Sustainable management in the street network means the influence of all its parts on traffic conditions and travel time. In order to reliably determine roundabouts parameters in the procedures of planning and the choice of sustainable method of traffic management, it is very important to know the values of the traffic flow parameters, particularly the speeds at the entry and exit leg, as well as in the circulatory zone. This article analyses the speed characteristics in traffic flow at urban roundabouts with different geometrical characteristics in the city of Banja Luka. The applied method for traffic data collecting in this research was the method of video recording processing, which excludes any influence on driver behavior. Furthermore, statistical analysis was conducted, which established the correlation between the achieved speeds and geometrical characteristics of the intersection. Due to roundabout characteristics, the research was focused on the access, that is, the entry leg, the segment of the circulatory zone and the exit leg. The research results showed there is a significant dependence between geometrical characteristics of certain elements of the roundabout on speeds. In the further course of the research, it was proved that the variation of speeds at the segments of roundabouts significantly affects the size of time losses and emission of pollutants, i.e., parameters based on which it is possible to objectively assess the possibility of sustainable implementation of the planned solution of roundabouts of similar geometry within the street network in cities similar to Banja Luka.

Modeling the Influence of Roundabout Deflection on Its Efficiency as a Noise Abatement Measure

“…The results of this part of the research indicated that for the analyzed roundabouts even a small change in the deflection around the central island had an influence on the noise levels generated by road traffic. Namely, the results showed that the decrease in deflection around the central island caused the increase in design speed on the fastest path segments on the entry, exit, and around the central island, which is in line with the previous studies on the vehicle speed on roundabouts [33,74,75]. The impact of this design speed increase on modeled noise levels was negligible until the median speed deviations reached 6 km/h (deflection decrease of 4 m).…”

“…To achieve a required reduction in noise levels, it is necessary to match the physical layout of the road to the intended speed and to provide as smooth a driving pattern as possible [20]. Modern roundabout, as a traffic calming device on which operating speed depends on the geometry (deflection around the circular island) [32,33], and a device that can carry smooth traffic flow by minimizing the start-stop operations of drivers, fulfills the abovementioned requirements for the effective noise abatement measure.…”

Insights into Simulated Smart Mobility on Roundabouts: Achievements, Lessons Learned, and Steps Ahead

“…Recent studies have concentrated on impact assessment in the "smart roundabout" domain (see Figure 1) and have delved into the potential of incorporating smart technologies into existing or planned roundabouts [14,15]. The goal is to leverage the benefits of integrating cutting-edge technological advancements into these infrastructures to fulfill the needs of sustainable traffic management [99]. Although not aiming for exhaustive coverage but rather to highlight key issues amenable to a common analytical approach, a search was conducted in the Scopus database, focusing solely on the term 'smart roundabout' within a 'title, abstract, and keywords' search.…”

Understanding Traffic Congestion via Network Analysis, Agent Modeling, and the Trajectory of Urban Expansion: A Coastal City Case

“…Traffic congestion can also be assessed from the graph theoretical perspective: for example, it has been established that the centrality properties of a street network strongly correlate with vehicular density [8,9]. The importance of identifying key structural points in the network is therefore fundamental to the design and application of infrastructural solutions, such as roundabouts [10][11][12] and overpasses [13,14], aiming to ensure a smooth flow of vehicles.…”